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  1. Replies
    9$$
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    189

    Disconnects Line/Load from Top

    Does NFPA 70 dictate that the line conductors must enter from the top terminals of the disconnect? I know NFPA 79 goes into detail about the physical placement of a disconnect inside of a sub panel,...
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    3$$
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    157

    Smart$, thanks. GoldDigger, I had to read what...

    Smart$, thanks. GoldDigger, I had to read what you wrote 3 times, but it is very clear and to the point. Thanks.
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    3$$
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    157

    Extension Grade vs Thermocouple Grade Wire

    I am trying to understand the difference between Extension Grade and Thermocouple Grade wire. I can only use Thermocouple grade wire at my sensing point, and I can use extenstion grade wire to...
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    12$$
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    Yes, the surface of the equipment is the 6th...

    Yes, the surface of the equipment is the 6th side. An HMI touchscreen, for example, mounted inside of a urethane enclosure that is then mounted on a stainless steel piece of machinery. In this...
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    12$$
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    Why does connecting the shield to ground matter? ...

    Why does connecting the shield to ground matter? Lets say I have a piece of stainless steel that is 1 foot by 1 foot, and I apply a 600mHz RF signal across it. Will more reflect off of the...
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    12$$
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    The wavelength for 600MHz is approximately 20...

    The wavelength for 600MHz is approximately 20 inches. I will need to keep any openings to less than 1/20th of that, so less than 1 inch..

    I am worried about the seams where the 5 sides plastic...
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    12$$
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    313

    I have a component that is radiating 600MHz. It...

    I have a component that is radiating 600MHz. It is housed inside a fabricated urethane enclosure. I would like to use conductive paint to coat the inside of the enclosure, which will effectively...
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    12$$
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    313

    RF Ground Using Copper Tape

    I have a plastic enclosure that will be coated with conductive paint on the inside. I would like to make a good RF ground to the machine enclosure from the conductive painted interior of the plastic...
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    4$$
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    359

    Twist lock plug, twist lock connector body..

    Twist lock plug, twist lock connector body..
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    4$$
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    359

    What are these Connectors Called?

    What are these types of plugs called? Would these still be considered pin and sleeve?
    12176
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    6$$
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    311

    RS485 Pull Up Resistors

    Why do some RS485 circuits require pullup/pulldown resistors be installed in the circuit, while some RS485 circuits do not require the pullup/pulldown resistors? Is it because some devices provide...
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    1$$
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    Radiated Emissions

    If I have electronics inside of a plastic enclosure, and then install the plastic enclosure on a piece of metallic equipment, will the radiated emissions be determined affected by the size of the...
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    42$$
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    Yes, 480Y/277, but there is a single pole fan...

    Yes, 480Y/277, but there is a single pole fan that is powered from a 480 primary to 240Y/120 secondary transformer.

    110.3 would be a catch all for situations like this... The load in question is...
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    42$$
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    It is a 460Y VAC system.."circuit breaker must...

    It is a 460Y VAC system.."circuit breaker must open all ungrounded conductors" is pretty clear, I will use double poles for these loads

    Is there anything similar for relays and contactors? Can I...
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    42$$
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    1,025

    Single Pole VS Double Pole Circuit Breaker

    If I have a single phase 460V (460V line to line) load, is there any reason to use a double pole circuit breaker over a single pole breaker?
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    8$$
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    336

    Can you please elaborate a little bit about what...

    Can you please elaborate a little bit about what you mean by it is not an equipment standard? 440 specifically calls out "motor driven air conditionaning and refrigerating equipment and to the...
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    8$$
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    336

    But strictly reading 440.4(B), I do not even have...

    But strictly reading 440.4(B), I do not even have to put the FLA on the nameplate. I have to put the volts, frequency, number of phases, minimum circuit ampacity, max rating of the branch OCPD, and...
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    8$$
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    336

    After studying NEC 440 again, since the...

    After studying NEC 440 again, since the compressors are not marked with an RLA, I have to put an RLA on the final equipment that uses the compressors. This RLA is determined by the rated operating...
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    8$$
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    The relevent standard would be IEC 61010 (also UL...

    The relevent standard would be IEC 61010 (also UL 61010). Here is what the document says:

    The equipment shall be marked with the following information:

    The maximum RATED power in watts, or the...
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    8$$
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    336

    FLA for an Industrial Machine

    Is it correct for a manufacturer to use the actual measured FLA of a machine, or do they have to use the summation of all the rated loads that could be on at the same time. The rated loads approach...
  21. If I want to list the largest motor FLA for a...

    If I want to list the largest motor FLA for a machine that has a refrigeration compressor as its largest motor, would I use the MOC of the motor?

    Refrigeration compressors use RLA (Rated Load...
  22. Petersonra, do you call it a suggestion since it...

    Petersonra, do you call it a suggestion since it is an NFPA79 requirement and not an NFPA70 requirement? If one were to follow 409.110 alone, I would not have to add the largest HP motor or load...
  23. Is this asking for the largest branch OCPD...

    Is this asking for the largest branch OCPD located within the equipment? Would this be so that the installation of the equipment overcurrent protection can be in compliance with NEC 409.21(C), or is...
  24. NFPA 79 (2015) Machine Nameplate Data Question

    I have a question about 16.4.1(5), where it is required to display the "Maximum ampere rating of the short-circuit and ground fault protective device, where provided".

    I am having trouble with the...
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    68$$
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    4,154

    Whatever advantages they have by using the single...

    Whatever advantages they have by using the single phase 230V to neutral approach vs our 120V/240V split-single phase approach is completely wiped out by their use of 50 Hz. Whereas 60Hz was...
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